1. Field of the Invention
The present invention relates to video technology, and in particular, relates to an apparatus for video encoding/decoding.
2. Description of the Prior Art
Digital video applications are commonplace in everyday life. Many video compression techniques and related standards are created to reduce the demand for the bandwidth of data transmission and the space for data storage, such as MPEG-1, MPEG-2, and MPEG-4, which are applied to multimedia, and H.263, which is applied to video conference. For instance, the frame rate of MPEG-1 is fixed, and the frame rate of MPEG-2 applied to DVD is also fixed, i.e. 29.97 frames per second. The frame rate of other video standards, such as MPEG-4 and H.263, are variable, that is, the frame rate can be adjusted during encoding process. The video compression techniques establish data blocks by discrete cosine transformation (DCT), motion compensation (MC), quantification, and variable length coding (VLC). The above-mentioned techniques are well known to those skilled in the art, the detailed descriptions are omitted.
Video bit-stream is generated in applications of video encoder for video transmission according to channel rate, and is transmitted to video decoder by network. In addition, Video bit-stream is generated in applications of video encoder for storing data according to the storage space, such as hard disk, and is loaded into the storage space, such as hard disk, by a writing/reading scheme of the storage space. Refer to FIG. 1. FIG. 1 shows a block diagram of the conventional apparatus for encoding/encoding video.
However, video packets are often lost because of transmission channel congestion, the lack of storage space, or busy storage equipment (i.e. apparent decade of write rate for hard disk due to densely segmenting) in practice. The conventional methods cannot adjust throughput in real-time, such that video data are lost to result in unacceptable video quality accordingly. And also, the conventional method under standards with a fixed frame rate cannot adjust bit-stream in real-time, such that video packets are lost to result in unacceptable video quality.
Therefore, it is important to provide a method with real-time bit-stream adjustment, which follows fixed or variable frame rate video standards, such that unacceptable video quality resulted from the loss of video data, non-smooth previous video playback, jumpy motion of video frame, etc., is improved.